Ethylene glycol is a high volume and widely used chemical product, one of its main uses being in the production of polyester plastics and fibres. It is widely manufactured by the hydration of ethylene oxide, which itself is made by oxidation of ethylene.
An alternative method of producing ethylene glycol that avoids the need for an ethylene derivative, and consequently the need for a steam cracker to produce ethylene, is to use C1 compounds as feedstock. Such processes include the reaction of carbon monoxide with formaldehyde, which results in the formation of glycolic acid, which can then be converted into ethylene glycol through processes such as hydrogenation, optionally after first being converted into a glycolic acid ester.
For example, He et al in Catalysis Today, 51 (1999), 127-134, describe the use of heteropolyacids as homogeneous catalysts for the carbonylation of formaldehyde or methyl formate.
U.S. Pat. Nos. 2,152,852 and 2,153,064 describe processes in which formaldehyde is contacted with an acidic catalyst and carbon monoxide, preferably with water, at elevated temperatures and pressures to produce glycolic acid. Inorganic and organic acids are stated to be suitable. In U.S. Pat. No. 2,153,064 pressures of 5 to 1500 atmospheres and temperatures of 50 to 350° C. are stated to be suitable.
U.S. Pat. No. 3,911,003 describes the production of hydroxyacetic acid (glycolic acid) from carbon monoxide, water and formaldehyde using a hydrogen fluoride catalyst. Temperatures of 0 to 100° C. and CO partial pressures of 10 to 4000 psig (1.6 to 273 atm) are stated to be suitable. The total pressure is stated as being only 1 to 10 percent higher than the CO partial pressure.
WO 01/49644 describes a process in which formaldehyde or a derivative thereof is reacted with carbon monoxide in the presence of an acid catalyst and a sulphone solvent, the acid catalyst having a pKa value of below −1. Halogenated sulphonic acids are stated to be preferred, although strongly acidic ion-exchange resins are also stated to be suitable as heterogeneous catalysts.